The present invention relates to an apparatus for recording and reproducing video and audio signals, and more particularly to an audio signal recording and reproducing apparatus which is suitable for recording the audio signal superimposed upon the video signal on the same track.
A typical example of apparatus for recording and reproducing the video and audio signals is the well known video tape recorder. The video tape recorder is required to be compact and have a longer recording time for unit length of tape, i.e., enhancement of the recording density. The higher recording density can save the tape length, allowing the use of a small tape cassette, thus contributing to the compactness of the apparatus. The above-mentioned demands are particularly persistent for video tape recorders for home use.
In existing practical video tape recorders, the video signal and the audio signal are recorded and reproduced on separate tracks on the magnetic tape. That is, in common home use video tape recorders, the video signal is recorded and reproduced in 2-head helical scanning system in which two rotary heads are used to form recording tracks askew the longitudinal direction of the magnetic tape, while the audio signal is recorded using a fixed head on a track parallel to the longitudinal direction of the tape. The recording density of such video tape recorders have been improved significantly owing to advanced magnetic tape materials and recording system in which the two rotary heads are arranged to have different azimuth so as to eliminate the guard band between two skew tracks. The recording density has been enhanced by about 17 times in the last decade, resulting in a significant reduction of the tape speed.
In consequence, it becomes difficult for recording and reproducing the audio signal by the fixed head to obtain the satisfactory wow and flutter characteristics, signal-to-noise (S/N) ratio and frequency response. Therefore, current household video tape recorders, in general, have an inferior sound quality relative to that of audio tape recorders. Because visual information has the primary importance whereas audible information is of secondary importance in household video tape recorders, the requirement for the sound quality is not as servere as it is in the case of audio tape recorders, and no practical problem has arisen.
However, more compact video tape recorders compared with current ones are demanded, and a higher recording density is needed to fulfill the request. The need of a small tape cassette needs a further reduction of the tape speed, which can be slower than that of popularized audio tape recorders. Thus, it is difficult to obtain the satisfactory performance in practical meaning by the conventional method of recording and reproducing the audio signal using a fixed head.